Seasonal variation of the surface boundary layer and the lower atmospheric boundary layer over boreal forests

北方森林表面边界层和低层大气边界层的季节变化

• 批准号: 12460063
• 负责人: OHTA Takeshi
• 金额: $ 9.22万
• 依托单位: Nagoya University (2001-2002)Iwate University (2000)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12460063/
• 关键词: Boreal forest; Energy and water cycles; Surface boundary layer; Atmospheric boundary layer; Climatic variables; 寒冷地森林; 水収支; エネルギー収支; 群落コンダクタンス; Big leaf model; 水・エネルギー循環; 寒冷地帯の森林; 水・熱循環; Big Leaf Model

Analyses on water and energy cycles at a Siberian pine forest are carried out, and the results are compared with those obtained at a Siberian larch forest. There are significant differences of seasonal variations on these cycles between the two forest sites. The parameters for a Jarvis type conductance model are similar to those obtained at the larch forest. There are clear relationships between the parameters in the Jarvis type model using not only our dataset but published datasets and the climatic variables using global grid datasets. This result suggests that physiological responses might be similar under same climatic conditions in spite of different vegetation types.Water cycles characteristics are investigated in a 0-order valley. Evapotranspiration from forest floors are strongly affected by spatial distributions of wind speed when soil moisture is high. On the other hand, understory evapotranspiration is affected by not only wind speed but also the spatial distribution of evaporation efficiency controlled by soil moisture under dry soil condition.The spatial and temporal distributions of latent and sensible heat fluxes in the lower atmospheric boundary layer are examined using a airplane. The results show that local circulation affects strongly the latent and sensible heat fluxes over the Siberian pine forest. This tendency agrees with the results obtained by the ground observation using a PBL tower mentioned above.

本文对西伯利亚松林的水分和能量循环进行了分析，并与西伯利亚落叶松林的结果进行了比较。两种森林样地的这些周期的季节变化存在显著差异。贾维斯型电导模型的参数是类似的落叶松林。不仅使用我们的数据集，而且使用已发布的数据集的Jarvis类型模型中的参数与使用全球网格数据集的气候变量之间存在明确的关系。这一结果表明，在相同的气候条件下，不同的植被类型的生理响应可能是相似的。当土壤湿度较高时，风速的空间分布对森林地表蒸散量有很大的影响。另一方面，林下蒸散量不仅受风速的影响，还受干燥土壤条件下土壤水分控制的蒸发效率的空间分布的影响。结果表明，局地环流对西伯利亚松林的潜热通量和感热通量有很强的影响。这一趋势与上述边界层塔地面观测结果一致。